Pedal switch



E G. STAUDE PEDAL SWITCH Dot. 2, 1934.

Filed March 11, 1931 En Jliazzde Aiiorneys Patented Oct 2, 1934 UNITED STATES PATENT OFFICE Claims.

This invention relates to improvements in brake-pedal-operated switches which can be used for controlling mechanisms which assist in applying the brakes, such as described in my copending application for Fluid power controlling mechanisms, Serial Number 375,846, filed July 3, 1929. In mechanisms of the kind disclosed in that copending application, a motor is used for operating a pump which controls a hydraulic system. The present invention is an improvement over that disclosed in mycopending application for Pedal switches, filed November 22, 1930, and bearing Serial Number 497,432. Among the objects are to provide a brake-pedal-controlled switch which can be closed as the pedal moves in brake-applying direction, and which can be opened as the pedal moves even slghtly in a reverse direction, and to accomplish these results without the use of an oscillating pedal switch which is located on or which forms a part of the pedal step.

In certain devices in which a switch is operated by a brake pedal, the circuit controlled by the switch is not open to stop the motor until the pedal is fully retracted. This is objectionable because it may happen that the pedal sticks and does not fully complete its brake-releasing stroke and in such instances, the circuit is not opened to stop the motor. In any event, the motor cannot be stopped until the pedal has completed its stroke, and there results an unnecessary and excessive current consumption, for example while on a. hill or while waiting for a go sign.

Among .the objects herein are: to so construct the switch and to so connect it in the system that on slight pedal depression electric contact will be made to close the motor circuit, and on continued depression, this contact will be maintained; and to so construct the switch that after the pedal has been depressed to any degree and if a slight reverse movement takes place (due to less muscular action on the part of the operator) the contact will be immediately broken, but can again be made substantially instantly if the pedal is again depressed. This arrangement allows what is known as inching. The

outstanding advantage here is that the switch is always closed at any point in the brake-applying stroke, is always open directly as the pedal recedes or reverses its movement, even though the distance-be as small as one-eighth of an inch.

It is the principal object of the present invention to maintain the switch in closed position as the pedal nears the last part of its stroke, that is as it nears it fully depressed position, corresponding to the maximum braking action. It is obvious that at this position, the brakes are powerfully applied, and that if the motor circuit were broken, and it ceased to act to assist in applying the brakes, the full reaction would be upon the leg of the driver, and it would be necessary for him to exert a much greatercounterforce to hold the pedal. Means is herein provided always to maintain a closed circuit when the pedal is nearly fully depressed, as, for example, during the last three-quarters of an inch of the stroke, although theoperator may ease up on the pedal and allow it to move in brake-releasing direction, so that there will be no lost motion,

and no undue reaction strain on the operator.

Features of the invention include the broader ideas of means, as well as all the details of construction shown.

Objects, features and advantages of the invention will be set forth in the description of the drawing forming a part of this application, and in said drawing Figure 1 is a longitudinal section through an automobile floor showing the device in elevameans for assisting brake-applying operation;

Figure 2 is a'longitudinal section of the switch showing its connection with the pedal and the position of the floor board with relation to the pedal; and

Figure 3 is a longitudinal sectional view illustrating the means by which the switch is operated and maintained in closed position during the last part of the pedal stroke.

Numeral 2 indicates the ordinary floor boards w the motor furnishes the power for operating the brake-applying assisting mechanism.

Secured to the upper end of the lever -3 is a tubular casing 15, the casing being pivoted to a shaft 14, which is secured by a clip 13 to the pedal 3. Slidably guided in, and passing through this casing is a rod 16 which is pivotally connected as at 17 to the engine. The rod 16 projects beyond the upper end of the casing 15-, when the pedal is fully retracted. Within the casing is immovably mounted a tubular contact block 20 having a conical contact surface 21, and the 'tion in association with electrically operable w block is secured by a suitable screw 22 which forms a binding post, and to which is secured the conductor 23, the opposite end of which connects with the suitable post 24 of the motor '1. The other terminal of the motor 25 is connected by suitable conductor 26 with a source of electric power 27 and the opposite side of the source is grounded as at 28, on the chassis, not shown. The bar 16 is grounded on the engine.

A contact member 30 is housed by the tubular element 15 but is freely movable longitudinally thereof and is provided with a conical contact portion 31 cooperable with the conical contact surface 21, to close the motor circuit. This element 30 is formed of two pieces which are held together in yieldable frictional contact with the rod 16 by an annular coiled spring 33 which has a constricting action. The element 30 is of such length that the casing 15 can move slightly on the rod 16 without engaging it or moving it. 'When the pedal is depressed from the position shown in Figure 2, 20 engages 30 to close the circuit. The element 30 has a yieldable frictional connection with the rod 16 and is translated by the element 21 when the pedal continues to move in the same direction, and as long as the movement continues in the same direction the contacts are held together. Whatever the direction of movement of the element 15, the element 30 is entrained, after a short motion of the element 15, independently of 30. When the pedal is retracted the entrainment is by means of the cap 34 acting on the opposite end of the element 30.

In order that the motor circuit remain closed during the last part of the pedal stroke, and when the greatest power is being transmitted to the brakes, that is when the pedal is fully, or almost fully, depressed, means is provided which acts during the last three-quarters of an inch of the extreme forward pedal stroke, to hold the switch closed, and keep the motor running until after the pedal has been retracted to some predetermined extent from its extreme forward position, sufficiently to have substantially reduced brake rod pull. This is done so that there will be no cessation of power application by the motoroperated brake power-supplying device, when the greatest power is being applied, and, therefore, the operator will not be called upon to exert that very much greater pressure which would at this time have to be exerted to hold the brakes.

The means by which the above functions are accomplished include a spring-operated device, in this instance a barrel 4Q having a slot 41, and having slidable therein a collar 42 held to the rod 16 by means of a set screw 43 which projects through the slot 41 and is slidable therein. A spring 44 normally holds the parts in the position shown in Figure 3. The stop 43 acts to limit movements of the element 40. The element 30 is provided with pins 46, which are slidably guided in cap 34, and project as shown. As the pedal nears the end of its forward stroke, these pins engage the end 47 of the barrel 40 and move the barrel against the action of the spring, compressing the spring. The reacting effect is to translate the pins in a direction counter to the motion of the casing 15, to correspondingly move contact 30 against contact 20, to close the circuit. Continued motion of 15 in the same direction maintains this circuit-closed condition, and increasingly compresses the spring. During the first part of pedal motion in opposite, or brakereleasing direction, the spring causes the barrel 40 to follow up and maintain the switch-closed position of elements 20, 30. If, during this period, the brake pedal is again depressed, there will be no feeling of lost motion. When the retracting motion is suflicient to cause the lower end of the slot to engage the stop, 43, as in Figure 3, continued retraction motion results in opening of the switch. The proper location of the barrel 40 is quickly determined by fully depressing the brake pedal and setting the collar 42 by means of the set screw 43 so that pins 46 engage the end of the barrel to depress it the required distance in order to obtain the follow-up action, on retraction of the pedal.

I claim as my invention:

1. A pedal, a support, first and. second contacts translatable on the support, the second contact having yieldable frictional connection withthe support, the first being movable by the pedal, said first contact having means adapted to translate the second in either direction, a stop movable on the support, a spring for urging the stop toward the contact, and means carried by the second contact adapted to engage the stop, and move said stop against the action of the spring to'cause the first contact to be movedto circuit closed position.

2. A pedal, a support, first and second contacts translatable on the support, the second contact having yieldable frictional connection with the support, the first contact being movable by the pedal, said first contact having means adapted to translate the second in either direction after a movement independently of the second, a stop movable on the support, means for limiting stop motion in opposite directions, a spring for urging the stop toward the second contact and means carried by the second contact adapted to engage the stop during pedal stroke, and move said stop against the action of the spring to cause the second contact to be moved to circuit-closed position.

3. A brake pedal, a support, first and second contacts translatable on the support, the second contact having yieldable frictional connection with the support, the first contact being movable by the pedal, said first contact having means adapted to translate the second in either direction after movement independently of the second,

a stop movable on the support, means for limiting stop motion in opposite directions, a spring for urging' the stop toward the second contact and means carried by the second contact adapted to engage the stop on a forward stroke of the brake pedal near the end of said forward stroke, and move said stop against the action of the spring to cause the second contact to be moved to circuit closed position.

4. A pedal, a support, an insulating member movable on the support by the pedal, a first contact secured to'the insulating member, a second contact movable independently of said member and having a yieldable frictional connection with the support, and adapted to be moved in one direction by the first contact, after a certain degree of motion of the first contact has occurred, said member having means for moving the second contact in opposite direction, a stop on the support, means for limiting stop motion in opposite directions, a spring for urging the stop toward the second contact, and means carried by the second contact adapted to engage the stop when the pedal is moved in one direction and near the end of the stroke and move the stop against the action of the spring to cause said second contact to be translated to circuit closed position.

" contacts translatable on the support, the second contact having yieldable frictional connection with the support, the first being movable by the pedal, said first contact having means adapted to translate the second in either direction after a certain amount of movement independently of the second, a stop movable on the support, means for limiting stop motion in opposite directions, a spring for urging the stop toward the second contact and means carried by the second contact adapted to engage the'stop on a forward stroke of the brake pedal near the end of the forward stroke and move said stop against the action or the spring to cause the second contact to be moved to circuit closed position.

6. In a device of the class described a movable control element, a switch structure including contact members, means by which the members can be controlled by the control member to be substantially instantly moved from one control position to another in correspondence to the motion of the control member so that such instantaneous motion occurs whatever the. position of the control member between its motion limits, and meansadapted to act during the last portion of the switch closingmovement oi the control member (within its control limits) to prevent opening motion of the contact members on reverse motion of the control member.

"I. In a device of the class described a movable control element, a switchstructure including contact members mounted on a conmion'support, means by which the members can be controlled by the control member to be substantially instantly moved from one control position toanother in correspondence tothe motion of the control member so that such instantaneous motion occurs whatever the position of the control member between its motion limit, the degree of motion of the control member being greater than that required to moverthe'members to opposite control positions, and means adapted to act during the last portion of the switch closing movement of the control member (within its control limits) to prevent'opening motion of the contact members on reverse motion oi-- the control member." Y

8. In combination with a movable control element, switching means controlled by said control element, means by which the switching means is moved to circuit-closed position on motion of the control element in one direction and is moved to circuit-open position on motion of the control element in an opposite direction, and means for holding the switch member in closedposition against the action or the first mentioned means,

when the control element arrives atia predetermined position and during a predetermined .de-f

gree ofcontinued motion thereaftenin the same direction, and for preventing motion of the switch means to circuit-open position by motion of said control element in said opposite direction.

9; In combination with an automobile having a brake pedal, electrically operable means for assisting braking efiort and controlled by the pedal, a switch structure, including contacts and connections by which they controlthe electrically operable means, means by which the contacts are controlled by the brake pedal to close and maintain a closed circuit during motion of the pedal in braking direction, and means adapted to act during that portion of brake pedal motion which corresponds substantially to the range of greatest braking power a plication, to prevent opening of the contacts on reverse motion of the brake pedal through a predetermined degree'of return movement to its initial nonbrake-applying position, whereby there is no violent reaction upon the leg of the driver, because the operation of the braking effort assisting means is maintained until the degree of braking power application is substantially lessened.

10,. In combination with an automobile including. a brake pedal, electrically operable means for assisting braking effort and controlled by ,the pedal, a switch structure including contact members and connections by which the members control the assisting means, means by which the.

members can be'controlled by the brake pedal to be substantially instantly moved from one con- 'trol position to another in correspondence to the on reverse motion or the brake-pedal through a predetermined degree of return movement of said pedal to its initial non-brake-applying position.

' Enwm G. s'rAUDn. 

